Pointing devices for use with computers and other companion electronic equipment are known in the art and include trackballs, joysticks, and variations of the computer “mouse”. Typically such devices require that the user move one element to control a cursor on a computer display, and then press or activate separate buttons to accomplish so-called “left-clicks” and “right-clicks”. Further it is common that the user must hold such devices in a fairly rigid position during use. While such tasks may not be overly challenging for many users, these tasks can be overwhelming to handicapped users, as will now be described.
A mouse or a trackball typically has a rotatable spherical element that the user moves over a fixed surface such as a desktop to cause movement of a cursor on a computer display. However such pointing devices are not absolutely coordinate devices in the sense that the user cannot tell by looking at the device where on the computer display the cursor may be found. Conventional pointing devices include one or more user-activated buttons, for example one button to left-click (and left double-click) and perhaps a second button to right-click, where the different click functions can cause different menu options to appear on the computer screen, or a program to execute (in the case of a left double-click). A generic mouse weighs perhaps 4 oz. and is perhaps 2″ wide, 5″ long, and 1″ in height. Commonly “left-click” and “right-click” buttons are located on the upper mouse surface, and are pressed, respectively, with the first and second fingers of the user's hand. Using the mouse to move a computer cursor on a display requires that the user move the entire mass of the mouse on the fixed surface such that the spherical element in the bottom of the mouse rotates.
More recently, the so-called optical mouse has found acceptance as a computer input device. An optical mouse often has the form factor of the older rotatable ball device. However instead of user-movement resulting in detectable rotation of a ball, an optical mouse replaces a rotatable ball with an optical emitter that directs light onto the work surface, and an optical sensor that detects light reflected by the work surface. As the user manipulates the mouse across the work surface, the optical sensor can discern relative changes in position by detecting the variation in different regions of the work surface, which variations typically are not apparent to the unaided eye. Exemplary optical mice are described in U.S. Pat. No. 6,281,882 (2001) and U.S. Pat. No. 6,433,780 (2002) to Gordon. However, manipulating an optical mouse requires essentially the same manual dexterity as manipulating a more conventional mouse, which dexterity is often not available to all would be users.
Prior art pointing mechanisms such as digitizer tablets can provide a degree of absolute coordinate information, but only while the digitizer stylus is in contact with the tablet surface. For instance if the stylus is contacting the upper right corner of the tablet, the user knows that the cursor will be in the upper right corner of the associated computer display. However as soon as the stylus is lifted from the digitizer tablet, the user can no longer look at the tablet and discern where on the computer display the cursor will be found. The stylus functions as the user-interface element to manipulate the cursor, and typically can be used to emulate left mouse-clicking.
But many users, especially physically handicapped users, find it difficult if not impossible to use prior art pointing mechanisms. Grasping and moving mice, or grasping and moving trackball devices to manipulate a cursor and then having to move a finger to click buttons may literally be impossible if the user suffers from carpal tunnel syndrome, arthritis, or perhaps has a hand prosthesis. A single user-interface element would be preferably, where the single element could be used to achieve cursor movement, and carry out the various mouse click functions. Even for non-handicapped users, the requirement of maintaining one hand on the device while pressing button(s) with a finger in a repetitive position, day-in, day-out, can result in physical disability, including tendonitis and carpal tunnel syndrome.
Some prior art pointing devices such as pressure or touchpads found on modern laptops, or the so-called TrakPointer™ mechanism found on IBM™ laptops can provide a dual function user-interface element that can be used for cursor movement and for left-clicking. However such devices do not provide absolute coordinate information to the user, do not provide right-clicking, and can be difficult to manoeuver, especially for the handicapped.
U.S. Pat. No. 5,821,921 (1998) and U.S. Pat. No. 6,107,991 (2000) to Osborn (applicant herein), which patents are incorporated herein by reference, disclosed pointing devices that provided the user with absolute coordinate information. The pointer mechanisms disclosed in these two patents included a user-grippable handle-like element that could better enable users, including handicapped users, to control cursor movement on a computer screen. The device described in Osborn '921 includes a peg-like element that a user could grasp to manipulate a cursor, and that could be pushed downward to emulate left mouse-clicking. The undersurface of the element would be moved by the user over a glide surface, and various resistive and/or optical mechanisms would determine the amount of movement in orthogonal x and y axes. Alternate embodiments of the '921 device included additional switches that a non-handicapped user could readily manipulate to emulate left and right mouse clicks. Among the advantages provided by devices according to the Osborn '921 and '991 patents was the substantial decrease in the magnitude of the mass of what the user was required to manipulate. For example rather than move a four ounce mouse, the portion of the device being manipulated weighed less than perhaps one ounce. Understandably for many handicapped users, and indeed for non-handicapped users, it is advantageous if computer control can be achieved while manipulating a smaller mass.
While the Osborn '921 and '991 pointing devices were absolute coordinate devices, there still was room for improvement. It turned out that double-clicking with the devices was difficult, especially for the handicapped. Excessive mechanical movement between the user-mechanism and the glide surface could occur between the movement of the first click and the second click. If the movement exceeds about three pixels on the computer display, the computer software will recognize two discrete and somewhat spaced-apart left mouse clicks, rather than a single left mouse double-click. In essence, while friction between the interface element and the underlying glide surface should be low for ease of user-controlled cursor movement, too low a coefficient of friction makes double-clicking difficult due to interface element movement between the two clicks.
What is needed is a pointing device with a single user-interface element that can be manipulated to move a cursor on a computer screen, while maintaining absolute coordinate information. Preferably the single element should be user-manipulable to emulate single and double left mouse-clicks and also a right mouse click, and should be manipulable even by handicapped users. Preferably the mass of the user-manipulated single-element should be low to reduce user fatigue. Further, the device should include a glide surface having a dynamic coefficient of friction that provides smooth rapid glide movement representing cursor movement, but that exhibits a higher coefficient of friction during mouse clicks to minimize undesired movement between mouse clicks. Preferably the device should sense the single user-interface movement using a mechanism whose form factor allows the device to be fabricated within a computer keyboard, if desired. Regardless of the device is implemented, device output to the companion computer or other equipment should of course be in an industry standard output format. Preferably such device should be implementable with a form factor sufficiently small to fit within a standard computer keyboard, if desired.
The present invention provides such a pointing device.